Biomarker Predicts Years of Service for Firefighters

An NIEHS-funded study shows that firefighters exposed to PAHs have epigenetic modifications that correlate with years of service and offer a potential biomarker for PAH exposure. Epigenetic modifications affect gene expression without changing the genetic code.

Firefighters are exposed to smoke and products of incomplete combustion, which often contain polycyclic aromatic hydrocarbons (PAHs). The researchers analyzed blood DNA from 18 firefighters and 20 non-firefighter controls, looking for a type of epigenetic change known as methylation in the promoters for four genes. They found that firefighters had a higher prevalence of promoter hypomethylation for the dual specificity phosphatase 22 (DUSP22) gene and that the extent of hypomethylation correlated with years of firefighting service but not with age. Cell studies confirmed that promotor methylation regulates DUSP22 expression.

This study’s findings indicate that gene expression of DUSP22 is modified epigenetically by environmental exposure. The researchers say that future studies need to examine whether hypomethylation of this gene can also predict later-life diseases, such as prostate cancer, that can result from long-term exposure to smoke.